BARACUDA-Legend-1

[bernte_one]

thanks maikl

that was the answer i hoped to get
this evening i have a little bit of time
will post results later

thanks all for help

[maikl]

Hi Bernd. You have no problem with low resistance (original Barracuda coil resistance 1R5) you have a problem with low inductance coil. My advice is to build a another similar coil, that'll put through the first and connected in series. You'll get the coil inductance 260 uH and resistance of 3.4 ohm. For this type of coil is probably better to use wire with a solid core (0,7mm-0,8mm) rather than Litz wire (due to less resistance). See the link below at the bottom http://fandy.vov.ru/Chance.htm

[bernte_one]

hello

low resistance- thats one thing i thought too- maybe i try a resistor 1R5 in serie with coil?

the shells are vacuum formed- the only trouble i have everytime is to cut clean lines in the wood plates

the coil is glued on a paper sheet with spraying glue
first spray a thin layer of glue and wait two minutes
the lay down the wire
when ready press it betwenn two plates with a weight on (i use wood plates)

next i try is a basket coil like for the chance pi
and a simple dual field

if anyone has an idea what i can do better on my simple planar coil please post

thanks bernd

[6666]

hello

with my last coil

http://www.geotech1.com/forums/showpost.php?p=143404&postcount=18

i got good results 2€ coin up to 20cmand good pinpoint
but tip127 gets hot after 1minute
with other coils no problem (but other have more micro Henry)
the resistance of that coils is similar like some others i build

this coils also make a summing sound i have some others with a lower L here they sing also but with other pi detectors too

is this a sign that the inductivity is too low?

need the tip127 a minimum of inductivity (coil works here also as a choke?)

in this case i would add a second layer to my planar coil
or have i only to add a resistor or something else when i use a low "L" coil?

regards bernds

130uH sounds a bit low, not much resistance for tip127, so maybe thats why its getting hot ?
very nice coil construction, how did you get it so neat ?

[wizz737]

Planer inductance

Hi Bernte One, What is the inductance of your planer coil? Did you vacuum form the coils in your pictures you posted? looks very nice !


Best Regards,

[bernte_one]

Hi bernte_one. What diameter wire you use for your last coil? Litze LIY 0.5mm?

hello
its LIY Litz H05V-K 0,5mm

http://www.ebay.de/itm/380306094301?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

regards bernd

[homefire]

Here is some good info on Litz wire.

[maikl]

Hi bernte_one. What diameter wire you use for your last coil? Litze LIY 0.5mm?

[bernte_one]

little heat problem

hello

with my last coil

http://www.geotech1.com/forums/showpost.php?p=143404&postcount=18

i got good results 2€ coin up to 20cmand good pinpoint
but tip127 gets hot after 1minute
with other coils no problem (but other have more micro Henry)
the resistance of that coils is similar like some others i build

this coils also make a summing sound i have some others with a lower L here they sing also but with other pi detectors too

is this a sign that the inductivity is too low?

need the tip127 a minimum of inductivity (coil works here also as a choke?)

in this case i would add a second layer to my planar coil
or have i only to add a resistor or something else when i use a low "L" coil?

regards bernds

[wizz737]

Bara air test results

Hi all, Here are the test results of my Bara with a good coil. (air test)

Canadian coins

$1 looney- 30cm
25 cent - 25cm
10 cent - 19cm
5 cent - 20cm
1 cent - 18cm
jar lid - 40 cm
soda can 50cm+

Test where indoors in not ideal conditions, lots of metal near by.

Can't wait to use the Bara on the beach this summer. I think I'll be digging some deep holes

Still have some tweaking to do however I'm happy with the results

[wizz737]

Bara working

Hi all, Replaced the 40106 and solved problem with low -5 volt supply. Bara is working stable now with good sensitivity with test coil. I picked up some 22 gauge Teflon silver 7 strand to make fast coil. will post results after testing.

Thanks to all for you input to help solve my problem. It takes good people to make a great forum and that's what we have here Geotect !

Best Regards.

[maikl]

40106 is sensitive to electrostatic. It's just one touch of the finger to be damaged or completely destroyed. Attention must be paid to electrostatic protection.

[TH Jim]

Hi folks,

I've had coils produce audible sound on both Bara and SP machines. Seems to be loose windings, shield or coil housing. Never had a problem with the -5v rail or a 40106.

Cheers, Jim.

[6666]

Hi Alex
yes we should be using the same chips

with my faulty 40106 chips, they had something wrong with them
on the bara I made I had a -5 volt rail that was down to about -3volt
changed it to a HEF40106BP made by NXD and its works at -4.98 v

on the other board I fixed, the -5volt rail was down to about -2.5 volts
and the coil had an audio sound, yes it was oscillating so I could hear it.

I tried that 40106 chip in my board and same thing, low voltage and audible coil sound
so changed to a CD40106BE made by TI, and it all works
these problems test us
cheers

[Alexismex]

Hello guys,
I encounter the problem for the 40106..... years ago...it is very simple :
every manufacturer has a different specification in this particular CI

Because the 40106 in the Bara fix Delay, window , etc.... if you has installed a 40106 from TI it want give you a "x" delay o window....change it with a different manu (ex NTE) and it will give you another delay o window ,with STMI another !!!!

Here is the trouble ... you must work with the same 40106 manufacturer !!!! and all the Bara will working the same